No, the first century Church was not sola scriptura.
In fact, Sola Scriptura fails its own test as the Bible never says all right doctrine must be based solely on it, so Sola Scriptura would be forced to reject the doctrine itself as unscriptural.
Sola Scriptura bases itself anyway on the Church Tradition of which books are canon and which aren't, which was only fixed much later.
However, the problem is that people are always trying to change or fit Christianity to their moulds, like Mormons or Jehovah's witnesses or whichever.
So if you base your beliefs on the only largely unchanged teachings we have of the earliest Church and Apostles, ie the Biblical Canon, it is likely you'll stay at least close to their doctrines. Tradition alone can veer far off course like various heretical groups, gnostics etc. clearly attest.
Besides, Sola Scriptura doesn't reject Church Tradition, it just holds that if Church tradition and Scripture seem to conflict, to trust Scripture on the point.